/*
 * Copyright 2001-2005 (C) MetaStuff, Ltd. All Rights Reserved.
 *
 * This software is open source.
 * See the bottom of this file for the licence.
 */

package com.googlecode.bluetools.dom4j.io;

import java.io.IOException;

import org.xml.sax.ContentHandler;
import org.xml.sax.ErrorHandler;
import org.xml.sax.SAXException;
import org.xml.sax.XMLReader;
import org.xml.sax.helpers.DefaultHandler;

import com.googlecode.bluetools.dom4j.Document;

/**
 * <p>
 * <code>SAXValidator</code> validates an XML document by writing the document to a text buffer and parsing it with a
 * validating SAX parser. This could be implemented much more efficiently by validating against the dom4j object model
 * directly but at least allows the reuse of existing SAX based validating parsers.
 * </p>
 * 
 * @author <a href="mailto:james.strachan@metastuff.com">James Strachan </a>
 * @version $Revision: 1.1 $
 */
public class SAXValidator {
	/** <code>XMLReader</code> used to parse the SAX events */
	private XMLReader xmlReader;

	/** ErrorHandler class to use */
	private ErrorHandler errorHandler;

	public SAXValidator() {
	}

	public SAXValidator(XMLReader xmlReader) {
		this.xmlReader = xmlReader;
	}

	/**
	 * Validates the given <code>Document</code> by writing it to a validating SAX Parser.
	 * 
	 * @param document is the Document to validate
	 * 
	 * @throws SAXException if a validation error occurs
	 * @throws RuntimeException DOCUMENT ME!
	 */
	public void validate(Document document) throws SAXException {
		if (document != null) {
			XMLReader reader = getXMLReader();

			if (errorHandler != null) {
				reader.setErrorHandler(errorHandler);
			}

			try {
				reader.parse(new DocumentInputSource(document));
			}
			catch (IOException e) {
				throw new RuntimeException("Caught and exception that should " + "never happen: " + e);
			}
		}
	}

	// Properties
	// -------------------------------------------------------------------------

	/**
	 * DOCUMENT ME!
	 * 
	 * @return the <code>XMLReader</code> used to parse SAX events
	 * 
	 * @throws SAXException DOCUMENT ME!
	 */
	public XMLReader getXMLReader() throws SAXException {
		if (xmlReader == null) {
			xmlReader = createXMLReader();
			configureReader();
		}

		return xmlReader;
	}

	/**
	 * Sets the <code>XMLReader</code> used to parse SAX events
	 * 
	 * @param reader is the <code>XMLReader</code> to parse SAX events
	 * 
	 * @throws SAXException DOCUMENT ME!
	 */
	public void setXMLReader(XMLReader reader) throws SAXException {
		this.xmlReader = reader;
		configureReader();
	}

	/**
	 * DOCUMENT ME!
	 * 
	 * @return the <code>ErrorHandler</code> used by SAX
	 */
	public ErrorHandler getErrorHandler() {
		return errorHandler;
	}

	/**
	 * Sets the <code>ErrorHandler</code> used by the SAX <code>XMLReader</code>.
	 * 
	 * @param errorHandler is the <code>ErrorHandler</code> used by SAX
	 */
	public void setErrorHandler(ErrorHandler errorHandler) {
		this.errorHandler = errorHandler;
	}

	// Implementation methods
	// -------------------------------------------------------------------------

	/**
	 * Factory Method to allow alternate methods of creating and configuring XMLReader objects
	 * 
	 * @return DOCUMENT ME!
	 * 
	 * @throws SAXException DOCUMENT ME!
	 */
	protected XMLReader createXMLReader() throws SAXException {
		return SAXHelper.createXMLReader(true);
	}

	/**
	 * Configures the XMLReader before use
	 * 
	 * @throws SAXException DOCUMENT ME!
	 */
	protected void configureReader() throws SAXException {
		ContentHandler handler = xmlReader.getContentHandler();

		if (handler == null) {
			xmlReader.setContentHandler(new DefaultHandler());
		}

		// configure validation support
		xmlReader.setFeature("http://xml.org/sax/features/validation", true);

		// configure namespace support
		xmlReader.setFeature("http://xml.org/sax/features/namespaces", true);
		xmlReader.setFeature("http://xml.org/sax/features/namespace-prefixes", false);
	}
}

/*
 * Redistribution and use of this software and associated documentation ("Software"), with or without modification, are
 * permitted provided that the following conditions are met:
 * 
 * 1. Redistributions of source code must retain copyright statements and notices. Redistributions must also contain a
 * copy of this document.
 * 
 * 2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the
 * following disclaimer in the documentation and/or other materials provided with the distribution.
 * 
 * 3. The name "DOM4J" must not be used to endorse or promote products derived from this Software without prior written
 * permission of MetaStuff, Ltd. For written permission, please contact dom4j-info@metastuff.com.
 * 
 * 4. Products derived from this Software may not be called "DOM4J" nor may "DOM4J" appear in their names without prior
 * written permission of MetaStuff, Ltd. DOM4J is a registered trademark of MetaStuff, Ltd.
 * 
 * 5. Due credit should be given to the DOM4J Project - http://www.dom4j.org
 * 
 * THIS SOFTWARE IS PROVIDED BY METASTUFF, LTD. AND CONTRIBUTORS ``AS IS'' AND ANY EXPRESSED OR IMPLIED WARRANTIES,
 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL METASTUFF, LTD. OR ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 * 
 * Copyright 2001-2005 (C) MetaStuff, Ltd. All Rights Reserved.
 */
